The invention relates to a condensation polymer having at least one dialkylamide endgroup connected through the polymer backbone to a unit derived from an alkylamide, the connection comprising at least one ester linkage.
According to a preferred embodiment, the polymer according to the invention contains at least two groups according to formula (I) 
H, a (C1-C20) alkylgroup or a (C6-C10) arylgroup;
B=a (C6-C24) aryldiradical or a (C2-C24) alkyldiradical;
R1, R2, R3, R4, R5 and R6 may, independently of one another, be chosen from the group of H, (C6-C10) arylgroups or (C1-C8) alkylgroups
R7 and R8 may, independently of one another, be chosen from the group of optionally heteroatom substituted (C6-C10) arylgroups or optionally heteroatom substituted (C1-C28) alkylgroups and n=1-4. Preferably, n=1.
According to a further preferred embodiment, the polymer according to the invention is a polymer according to formula (II): 
H, a (C1-C20) alkylgroup or a (C6-C10) arylgroup; 
B=a (C6-C24) aryldiradical or a (C2-C24) alkyldiradical; 
R1, R2, R3, R4, R5 and R6 may, independently of one another, be chosen from the group of H, (C6-C10) arylgroups, (C1-C8) alkylgroups or xe2x80x94CH2xe2x80x94OX2;
R7 and R8 may, independently of one another, be chosen from the group of optionally heteroatom substituted (C6-C10) arylgroups or optionally heteroatom substituted (C1-C28) alkylgroups.
Preferably, R1 and R2 are both equal to H.
According to a further preferred embodiment, the polymer according to the invention has a number of dialkylamide endgroups xe2x89xa73 and the polymer is represented by formula (III): 
B=a (C6-C24) aryldiradical or a (C2-C24) alkyldiradical; 
R3 and R6 are chosen from the group of H, (C6-C10) arylgroups and (C1-C8)alkylgroups;
R7 and R8 may, independently of one another, be chosen from the group of optionally heteroatom substituted (C6-C10) arylgroups or optionally heteroatom substituted (C1-C28) alkylgroups.
In all above embodiments, preferably, R3 and R6 are (C1-C4) alkyl groups, more preferably a methyl- or ethylgroup. In all above embodiments, preferably, R7 and R8 are optionally hetero-atom substituted (C1-C20) alkyl groups, more preferably, R7 and R8 are hetero-atom substituted C2-, C3- or C6- alkylgroups. R7 and R8 may be substituted with a group selected from the group of alcohol, ether, ester, cyanide, carbonate, urethane, urea, amide, imide, amine, imine, imidazole, oxime, sulfide, thiol, thiourea, sulfon, sulfoxide, sulfate, fosfate, fosfine, fosfinoxide, silane, silicone, silicate, fluoro, chloro, bromo or iodo groups. Suitable choices for R7 and R8 are di(m)ethylaminoethyl, di(m)ethylaminopropyl, di(m)ethylaminohexyl, tri(m)ethylsilylpropyl, tri(m)ethoxysilylpropyl, perfluoro-octyl, perfluoro-octyl-(m)ethyl, (m)ethoxy-ethyl, (m)ethoxy-2-propyl, maleimido-propyl, maleimido-hexyl, octenylsuccinimido-hexyl, hexahydrophthalimido-hexyl, 2-(benz)imidazole-ethyl, difenylfosfino-ethyl, furfuryl, cyanoethyl, or cyanopropyl groups. R7 and R8 can also be part of the same optionally substituted cyclic group, such as a morfoline, thiomorfoline, piperidine, pyrrolidine, oxazolidine, thiazolidine or piperazine group.
In all formulas in this application in which R-groups are present, the R groups may together or with neighbouring carbon atoms form part of a cycloalkyl group.
Depending on the starting monomers chosen, B, R1, R2, R3, R4, R5, R6, R7 and R8 in the molecule or mixture of molecules can be selected to be the same or different.
B is optionally substituted, preferably with a (C1-C26) alkyl group. Preferably, the alkylgroup is chosen from the group of methyl, octenyl, nonenyl, decenyl, undecenyl or dodecenyl. Suitable choices for B are (alkyl-)1,2-ethylene, where the alkyl is defined as above, (methyl-)1,2-ethylidene, 1,3-propylene, (methyl-)1,2-cyclohexyl, (methyl-)1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 2,3-norbornyl, 2,3-norbornen-5-yl or (methyl-)1,2 cyclohex-4-enyl radical.
Preferably, the weight average molecular mass of the polymer according to the invention is between 600 g/mol and 50,000 g/mol, more preferably between 800 g/mol and 25,000 g/mol.
Preferably, the number average molecular mass is between 500 g/mol and 15,000 g/mol, more preferably between 700 g/mol and 4,000 g/mol.
Preferably, the average number of dialkylamide endgroups per molecule is between 2 and 250, more preferably between 3 and 50.
The polymer according to the invention can be linear or branched. The linear polymer according to the invention generally comprises amide and ester units alternating along a chain as follows:
xe2x80x94A-Exe2x80x94Axe2x80x94Exe2x80x94Axe2x80x94Axe2x80x94Exe2x80x94Axe2x80x94Exe2x80x94Axe2x80x94Exe2x80x94Axe2x80x94
wherein a diamide (Axe2x80x94A) unit is coupled with alternating ester (E) and amide (A) units.
A branched polymer according to the invention generally comprises amide and the ester units alternating along the main and side chains as follows: 
wherein a diamide (Axe2x80x94A) is coupled with alternating ester (E) and amide (A) units.
Preferably, in the branched polymer according to the invention a (xcex2)-hydroxyalkylamide group is present, which can be both present as a bis-(xcex2)-hydroxyalkylamide endgroup, such as 
or as a pendant side chain group, such as 
Preferably, the molar amount of amide units in the chain is higher than the molar amount of ester units.
The invention also relates to a process for the production of the polymer according to the invention.
According to a preferred embodiment, the polymer according to the invention can be obtained through polycondensation of a mono- and/or bis-hydroxyalkylamide of a dicarboxylic acid in the presence of a mono-dialkylamide of a dicarboxylic acid.
Preferably, the mono-hydroxyalkylamide of the dicarboxylic acid is a compound according to formula (IV): 
Preferably, the mono-dialkylamide of the dicarboxylic acid is a compound according to formula (V): 
Preferably, the bis-hydroxyalkylamide of the dicarboxylic acid is a compound according to formula (VI): 
wherein (in formula""s IV, V and VI)
R1, R2, R3 and R4 may, independently of one another, be chosen from the group of H, (C6-C10) arylgroups or (C1-C8) alkylgroups;
R7 and R8 may, independently of one another, be chosen from the group of optionally heteroatom substituted (C6-C10) arylgroups or optionally heteroatom substituted (C1-C28) alkylgroups and
B may be a (C6-C24) aryldiradical or a (C2-C24) alkyldiradical.
According to a further preferred embodiment, the polymer according to the invention can be obtained in a one-step procedure by reacting a cyclic anhydride, a dialkylamine and an alkanolamine, at room temperature or at an elevated temperature, preferably between about 20xc2x0 C. and about 120xc2x0 C., to form hydroxyalkylamide and dialkylamides, after which, at an elevated temperature, preferably between 120xc2x0 C. and 250xc2x0 C., a i is obtained through polycondensation with water being removed, preferably through distillation.
The one-step procedure can take place with or without a solvent. Suitable solvents are water or an organic solvents, such as methyl-isobutylketon, butylacetate, toluene or xylene.
The removal of water through distillation can take place at either reduced or elevated pressure, such as at a pressure higher than 1.105 Pa, in a vacuum ( less than 1.105 Pa) or azeotropically.
Preferably, the cyclic anhydride is an anhydride according to formula (VII): 
in which B has the meaning as specified above.
Examples of suitable cyclic anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, naphtalenic dicarboxylic anhydride, hexahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, norbornene-2,3-dicarboxylic anhydride, naphtalenic dicarboxylic anhydride, 2-octene-1-yl-succinic anhydride, 2-nonene-1-yl-succinic anhydride, 2-decene-1-yl-succinic anhydride, 2-undecene-1-yl-succinic anhydride 2-dodecene-1-yl-succinic anhydride, maleic anhydride, (methyl)succinic anhydride, glutaric anhydride, 4-methylphthalic anhydride, 4-methylhexahydrophthalic anhydride, 4-methyltetrahydrophthalic anhydride, maleinised poly-isobutane, maleinised polybutadiene and the maleinised alkylester of an unsaturated fatty acid.
Preferably the alkanolamine is compound according to formula (VIII): 
R1, R2, R3, R4, R5 and R6 may, independently of one another, be chosen from the group of H, (C6-C10) arylgroups, (C1-C8) alkylgroups or CH2OH and n=1-4. More preferably, n=1.
The alkanolamine may be a monoalkanolamine, a dialkanolamine, a trialkanolamine or a mixture hereof.
If monoalkanolamines are used in the process according to the invention, linear polymers with a functionality of 2 can be obtained. Depending on the application desired, a linear or an entirely or partly branched polymer can be chosen, in which case the degree of branching can be set by choosing the type of alkanolamine.
If a highly branched structure with a high functionality is desired, di- or trialkanolamines are used as the starting compound.
Examples of suitable mono-xcex2-alkanolamines include ethanolamine, 1-(m)ethyl ethanolamine, n-butyl ethanolamine, 1-(m)ethyl isopropanolamine, isobutanolamine, xcex2-cyclohexanolamine, n-butyl isopropanolamine and n-propanolamine.
Examples of suitable di-xcex2-alkanolamines are 3-amino-1,2-propanediol, 2-amino-1,3-propanediol diisobutanolamine (bis-2-hydroxy-1-butyl)amine), di-xcex2-cyclohexanolamine and diisopropanolamine (bis-2-hydroxy-1-propyl)amine).
A suitable trialkanolamine is, for example, tris(hydroxymethyl)aminomethane.
Preferably a xcex2-alkyl-substituted xcex2-hydroxyalkylamide is used. Examples are (di)isopropanolamine, cyclohexyl isopropanolamine, 1-(m)ethyl isopropanolamine, (di)isobutanolamine, di-xcex2-cyclohexanolamine and/or n-butyl isopropanolamine. Most preferably, diisopropanolamine and diisobutanolamine are used. The choice of a xcex2-alkyl-substituted xcex2-hydroxyalkylamide results in a polymer with improved resistance to hydrolysis.
Preferably, the dialkylamine is an amine according to formula (IX) 
in which R7 and R8 may, independently of one another, be chosen from the group of optionally heteroatom substituted (C6-C10) arylgroups or optionally heteroatom substituted (C1-C28) alkylgroups.
Examples of suitable dialkylamines include: di(m)ethylamine, dibutylamine, dioctylamine, di-2-ethylhexyl-di(m)ethylamine, dibutylamine, dioctylamine, di-2-ethylhexyl-amine, distearylamine, diallylamine, dicrotylamine, N-(m)ethylallylamine, bis(aminopropyl)amine, bis(aminohexyl)amine, N-(m)ethyl-aminopropylamine, bis(di(m)ethylaminopropyl)amine, bis(di(m)ethylaminohexyl)amine, bis(di(m)ethylaminoethyl)amine, bis(trimethylsilylpropyl)amine, bis(tri(m)ethoxysilylpropyl)amine, bis(perfluorooctyl)amine, bis(perfluorooctyl(m)ethyl)amine, bis(methoxyethyl)amine, N-(m)ethylmethoxypethylamine, bis(methoxy-2-propyl)amine, bis(maleimidohexyl)amine, bis(octenylsuccinimidopropyl)amine, bis(hexahydrophthalimidohexyl)amine, difurfurylamine, dicyano(m)ethylamine, bis(difenylfosfinoethyl)amine, morfoline, thiormorfoline, piperidine, pyrrolidine, (2-fenyl)oxazolidine, thiazolidine, piperazine, 2,2,6,6,tetramethylpiperidine, iminodibenzyl, imidazole.
The anhydride:[alkanolamine+dialkylamine] equivalent ratio is generally between 1.5:1.0 and 1.0:2.0, preferably, between 1.0:1.0 and 1.0:1.8, more preferably, between 1:1.05 and 1:1.5.
The alkanolamine:dialkylamine equivalent ratio can be chosen according to the molecular weight and the number of xcex2-hydroxyalkylamide and dialkylamide groups desired and is generally between 100:1 and 1:3, preferably between 10:1 and 1:2.
If only dialkylamide endgroups are desired in a highly branched structure, molar equivalent ratio""s of dialkanol amine:dialkylamide:anhydride can be chosen as for example 1:3:3, 2:4:5, 3:5:7, 4:6:9, or generally as n:n+2:2n+1, in which n is an integer, larger than or equal to 1.